1. Field of the Invention
The present invention relates to a radiation detection apparatus and a radiographic system.
2. Description of the Related Art
A radiation detection apparatus includes a sensor unit having a plurality of two-dimensionally arranged photoelectric conversion units and a scintillator layer which converts radiation into light. A sensor protective layer can be provided on a sensor unit, and a scintillator underlying layer for the vapor deposition of the scintillator layer can be provided under the scintillator layer. For example, Japanese Patent Laid-Open No. 2006-078471 discloses a structure including the above two members between the sensor unit and the scintillator layer.
There is a problem in that light generated in the scintillator layer in a region immediately above each photoelectric conversion unit leaks into other photoelectric conversion units (for example, adjacent photoelectric conversion units) to degrade the sharpness of the radiographed image. One conceivable cause of this problem is that some of generated light obliquely propagates instead of vertically propagating toward the sensor unit. When this apparatus includes a plurality of members, incident light leaks into other photoelectric conversion units due to the refraction and reflection of light caused by refractive index differences on the interfaces between the respective members. This is another conceivable cause of the problem. However, for example, Japanese Patent Laid-Open No. 2006-078471 has not disclosed any way of how to select refractive indices of members constituting the radiation detection apparatus from predetermined ranges of the respective members. That is, there is no consideration to the above problem.